A possible way to analyze a sample is to irradiate the sample with X-rays and measure a resulting signal. For example, U.S. Pat. No. 9,551,677, describes a method that includes directing an X-ray beam to be incident at a grazing angle on a location on a surface of the sample. X-ray fluorescence excited at the location is measured. A reflection angle of the X-ray beam from the surface, and a transmission angle of the X-ray beam, are measured. An angle of incidence of the X-ray beam on the surface is evaluated using the measured reflection and transmission angles, and the measured X-ray fluorescence is analyzed using the evaluated angle of incidence.
As another example, U.S. Pat. No. 7,551,719 describes an apparatus that includes a radiation source for analysis of a sample. The apparatus is adapted to direct a first, converging beam of X-rays toward a surface of the sample and to direct a second, collimated beam of the X-rays toward the surface of the sample. A motion assembly moves the radiation source between a first source position, in which the X-rays are directed toward the surface of the sample at a grazing angle, and a second source position, in which the X-rays are directed toward the surface in a vicinity of a Bragg angle of the sample. A detector assembly senses the X-rays scattered from the sample as a function of angle while the radiation source is in either of the first and second source configurations and in either of the first and second source positions. A signal processor receives and processes output signals from the detector assembly so as to determine a characteristic of the sample.
U.S. patent application Ser. No. 15/717,961 titled, “Closed-Loop Control of X-ray Knife Edge,” filed Sep. 28, 2017, whose disclosure is incorporated herein by reference, describes an apparatus for X-ray scatterometry that includes an X-ray source, which directs an X-ray beam to be incident at a grazing angle on an area of a surface of a sample, and an X-ray detector measures X-rays scattered from the area. A knife edge is arranged parallel to the surface of the sample in a location adjacent to the area so as to define a gap between the surface and the knife edge and to block a portion of the X-ray beam that does not pass through the gap. A motor moves the knife edge perpendicular to the surface so as to control a size of the gap. An optical rangefinder receives optical radiation reflected from the surface and outputs a signal indicative of a distance of the knife edge from the surface. Control circuitry drives the motor responsively to the signal in order to regulate the size of the gap.
A possible way to increase the detection ability of an X-ray detector is to shield the detector against stray X-ray radiation. For example, U.S. Pat. No. 8,693,635 describes an X-ray detector assembly that includes an integrated circuit, which includes an array of detector elements and a readout circuit adjacent to the array and coupled to read charge out of the detector elements. A non-metallic shield is positioned over the readout circuit so as to prevent X-rays from striking the readout circuit.
In another field that uses X-rays, German Patent Application Publication DE102005029511 describes a device that comprises a screen consisting of at least two materials for absorbing X-ray radiation. Each X-ray radiation absorption coefficients of the materials differ in the energetic layer of their K-edges. An independent claim is also included for an X-ray device comprising a solid body detector and the above screen. Preferred Features: The screen consists of three materials whose X-ray radiation absorption coefficients differ in the energetic layer of their K-edges.
In yet another field that uses X-rays, U.S. Patent Application Publication 2008/0165922 describes a computed tomography (CT) collimator that includes a first radiation absorbent lamination having a plurality of apertures formed therethrough. Each aperture formed through the first radiation absorbent lamination is aligned with a respective axis formed between a corresponding pixelating element and an x-ray emission source. The collimator includes a second radiation absorbent lamination having a plurality of apertures formed therethrough, each aperture formed through the second radiation absorbent lamination aligned with the respective axis formed between a corresponding pixelating element and the x-ray emission source. A spacer is positioned between the first and second radiation absorbent laminations.